Shell-fuse with safety device.



H. NO'RDENFELT.

SHELL FUSE WIT SAFETY DEVICE. l APPIlloATIoN FILED APB. 9. 1912.

y Panama Feb.1s`,1913.

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UNITED PATENT @FF-fat@ GULLSPNG, OF BOFORS. SWEDEN.

SHELL-FUSE `W'I'IH SAFETY DEVICE.

lib-)3.357.

Application filed April 9,

Specification of Iietters Patent.

Patented Feb. 18.1591 3.

1912. Serial No. 689,472.

Tf, (f77 whom. t may concern.'

le it known that l, HENRIK Nonnen*- i-izixr` a subject of the King ofSweden, residing at Bofors, Sweden, have invented new and usefulImprovements in Shell- Fuses with Safety Devices, of which the followingis a specification.

ln fuses for high explosive shells it has always been desirable that thefuse shall remain inoperative, i'. e. that it shall not be possible tobring the charge to explosion, before the projectile has passed not onlythrough the barrel but also to a certain distance in 'l'i-ont of themouth of the gun. For this purpose, a longitudinally movable, simple orcomposite'member has been used, said member being moved forward when theacN celeration of the projectile ceases, either on account of itsinertia or under the .action of a compressed spring or both, and makingthe fuse operative on impact so as to permit the explosion, only aftermoving through a certain distance. lt has however been found, that inusing such a safety device well as all those known heretofore which arebased only upon mechanical principles the distance in front of thebarrel mouth through which\ the projectile travels before being madeoperative only will amount to a few meters, the safety for the servicemen of the gun thus being unsatisfactory.

The present invention has for its object to provide a device forsurmounting the aforesaid inconvenience and consists in in troducing acertain determined resistance against the forward niovenient of theaforesaid longitudinally niovable member, thus retarding the saidmovement and the nioment in which the fuse becomes operative.

The invention is illustrated in the accompanying drawing whereV4 Figuresl and 2 show two different forms of fuses embodying the same in alongitudinal section and l"ig;s.. -5 three different forms of memberscharacteristic to the involition.

ln Fig. l which shows a base fuse the stationary fuse body consists ofthree parts y, z, l. the last-mentioned of which embraces the (-,liargeyj. 'The part 71.V Carries (he igniting needle i' aol en'ibraccs partlyby means olf suilablil recesses balls (l which also engage rocosa in thehammer c carrying the ignltine`- cap the movement of said hammer thusbeing pi" culi-if. The balls Il aro hcld I against vmoving out of therecesses in the l hammer e by means of a surrounding ring or sleeve Vhenthe gun is fired, a sleeve a. surrounding the Sleeve c is moved backwardon account of its inertia and compresses a celeration again moves thesleeve o forward, the said sleeve having meanwhile been coupled to thesleeve c by means of a resilient tiange so as to carry forth the latterwhen moving forward. The balls CZ then are released and are thrown outby the centrifugal force, whereupon the fuse is operative, the hammernow being kept away from the igniting needle Z only by the weak springb.

As the forward movement of the parts a and o, as above stated, begins assoon the acceleration of the projectile has ceased, or even somewhatbefore this moment, the operative condition of the fuse will be reachedtoo soonif no special steps are taken to prevent this circumstance.According to the present invention, such steps are taken in that a`resistance against the movement of the part c is introduced. A simplearrangement for obtaining such al resistance is to cause a pin m securedto the part o to engage a slot n in the stationary fuse body L, or viceversa. The slot n may in some cases be straight and a sullicientresistance may still be obtained on account of the pressure and frictionbetween the pin and the side of the slot caused by the rotation of theprojectile. ln other cases, it may be found suitable to make the slotciufved or its walls uneven for obtaining the necesary increasedresistance against the movement of the part c. Dif-V ferent examples ofthis principle are shown in Figs, 315-5. By an appropriate shape of theslot the entering of the operative state of the fuse can be retarded atwill.

Fig. i2 illustratesan application of the invention to a point fuse,Further, in this form only one longitudinally movable member c ispresent, said member moving backward at the firing of the gun andcompressing the spring which after the ceasing of the acceleration-moves the member' c forward again. in this movement, the said memberpasses beyond its original position, because a couple of locking memberso situated in front. of the same meanwhile have been removed hy'lhecentrifugal` force against the action ol' springs y resting against nutsg. lhe retardation of the movement of the spring f which upon theceasing of the afseiilectingg the friction other devices may be usedthan pins'engaging slots. *L

Having now particularly described the 11atui'e of my invention and themanner of its operation, what claim is: l. In safety devices for shellfuses, a hammerA e firing pin7 locking members for normally preventingContact between said hammer and firing pin7 a longitudinlly movablemember for releasing said locking members, and a pin onKsaidlongitudinally movable member engaging a slot in a stationary part ofthe fuse.

2. In safety devices for shell fuses, a hammer a' firing pin, lockingmembers for normally preventing` Contact between said hammer and firingpinz e. longitudinally movable member for releasing said lockingmembers, and a pin on seid longitudinally movable member engaging acurved slot in a stationary part of the fuse. Y Y

In testimony whereof I have signed my name to this specification in. thepresence of two subscribing Witnesses.

HENRIK NORDENFELT. Witnesses A. R. ENGBURG, EMIL-Olsson.

